In some applications of power semiconductors, such as in bridge circuits for motors, a plurality of chips are placed together as a chip stack in a package. This both saves space for the complete system and also reduces the length of interconnects between the chips.
German patent DE 196 35 582 shows such a bridge circuit containing high-side and low-side switches, for which a second chip is mounted on a first chip such that the load paths of the first and second chip are connected in series. The second chip, which lies on top and contains the low-side switch is here designed to be smaller than the first chip, which lies below and contains the high-side switch. This ratio should be inverted, however, in many bridge circuits, for example, because the low-side switch is subject to a far greater load. The current-carrying capability of the power semiconductor component is hence restricted by the size of the low-side switch.